A treatable rare cause of chorea: polycythemia vera
The present case has been published in the journal Neurology. A 72-year-old woman developed progressive choreic movements involving the right hemibody and the orofacial muscles (video available). Her examination was otherwise unremarkable, without ataxia.

Brain MRI, blood glucose, thyroid function, and rheumatologic panel were unremarkable. Genetic testing for Huntington disease and C9orf72 expansions were negative. Initial hematocrit and hemoglobin levels were normal, but increased to abnormal values (56% and 18.5 g/dL) 1 year after chorea onset.

The JAK2V617F mutation was positive, suggesting a diagnosis of chorea due to polycythemia vera. Chorea disappeared with phlebotomy and hydroxyurea.

Key takeaway:-
- Neurologists should suspect this rare treatable entity in elderly patients with chorea even with initially normal hematocrit levels.

Source: https://pxmd.co/nsZlm